xfrm: fix stale skb->prev after async crypto steals a GSO segment (CVE-2026-68426) | HOL Guard CVE

Critical · CVSS 9.8CVE-2026-68426

xfrm: fix stale skb->prev after async crypto steals a GSO segment

Answer in brief

CVE-2026-68426 records a Critical severity (CVSS 9.8) vulnerability in xfrm: fix stale skb->prev after async crypto steals a GSO segment. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Aug 10, 2026Updated Aug 17, 2026Source checked Sep 24, 2026First seen by HOL Aug 10, 2026Material review Aug 17, 2026

Upstream Advisory

Key facts

Risk: Critical · CVSS 9.8
Exploitation: Not marked as known exploited
Affected software: 2 mapped packages or products
Fix availability: Available

Why this deserves its current priority

CVSS is 9.8. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
Linux/Linuxgeneric	>=f53c723902d1ac5f0b0a11d7c9dcbff748dde74e <33e1b0d25ca0d2818c635ff80e6aa0d295e08a98 \|\| >=f53c723902d1ac5f0b0a11d7c9dcbff748dde74e <bbca7cc3b2b4b10afbfee99b81d9ee78f5423046 \|\| >=f53c723902d1ac5f0b0a11d7c9dcbff748dde74e <3f4c3919baf0944ad96580467c302bc6c7758b00	33e1b0d25ca0d2818c635ff80e6aa0d295e08a98, bbca7cc3b2b4b10afbfee99b81d9ee78f5423046, 3f4c3919baf0944ad96580467c302bc6c7758b00
Linux/Linuxgeneric	4.16	Not reported

Recommended response

Check inventory. Check lockfiles and deployed manifests for Linux/Linux, Linux/Linux.
Review the reported fix. Update Linux/Linux to 33e1b0d25ca0d2818c635ff80e6aa0d295e08a98 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Aug 10, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Aug 17, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Aug 10, 2026

Sources and claim methodology

Upstream source description

In the Linux kernel, the following vulnerability has been resolved: xfrm: fix stale skb->prev after async crypto steals a GSO segment skb_gso_segment() leaves the segment list head with ->prev pointing at the last segment, an invariant validate_xmit_skb_list() relies on when it sets its tail pointer (tail = skb->prev). When validate_xmit_xfrm() walks a GSO list and some segments are stolen by async crypto (->xmit() returns -EINPROGRESS), those segments are unlinked from the list but the head ->prev is never updated. If the last segment is the one stolen, the returned head still has ->prev pointing at it, even though it is now owned by the crypto engine and may be freed. validate_xmit_skb_list() later does tail->next = skb, writing through that stale pointer -- a use-after-free. Repoint skb->prev at the last retained segment before returning.

Quoted source text, attributed separately from HOL analysis.